Tech Mahindra — never received relieving letter

I worked in techm for nearly 1 year and i also put a formal resignation letter and i was on notice period for 45 days. Still the company never have me a relieving letter. They emailed me that they will give the relieving letter if dues are settled but even after settling all the dues, i had never recieved a relieving letter from the company. Which was a big form of cheating from the company side. Tech mahindra company will never give you a relieving letter even if you work there for 1 year.